Re: [PATCH] new ELF64 patch

Re: [PATCH] new ELF64 patch

[Ruslan Nikolaev]

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Hi!

I sent new patch for mutiboot:
http://lists.gnu.org/archive/html/grub-devel/2005-07/msg00130.html

 Is it correct now?

By the way... I have seen that grub2 has a 4Gb limit when detecting
memory size and mmap. I think that is not good for both x86 and x86_64.
i686 for example can use 64 Gb of RAM. As for x86_64 it is 2^52 bytes. I
can try to fix this... But I also need an answer about ELF64 multiboot.

Best regards, Ruslan.

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Re: [PATCH] new ELF64 patch

[Joel Buckley]

Ruslan Nikolaev wrote:

> I have seen that grub2 has a 4Gb limit when detecting memory size and 
> mmap. I think that is not good for both x86 and x86_64. i686 for 
> example can use 64 Gb of RAM. As for x86_64 it is 2^52 bytes. I can 
> try to fix this... But I also need an answer about ELF64 multiboot.
>
> Best regards, Ruslan.
>
Ruslan,

I can see this would be a problem for the final running kernel.
However, is 4GB sufficient for kernel loading & kernel memory discovery?

I am interested in situations were 4GB would not be sufficient.
Say, having grub2 being utilized for full device discovery for a 
minimalistic kernel...
Or, having grub2 be the minimalistic kernel...

Forgive me, I am still learning the Weirding Ways ;)

Regards,
Joel

Re: [PATCH] new ELF64 patch

[Yoshinori K. Okuji]

On Monday 18 July 2005 05:34, Joel Buckley wrote:
> I can see this would be a problem for the final running kernel.
> However, is 4GB sufficient for kernel loading & kernel memory discovery?

You are absolutely right. The idea behind is that GRUB itself does not require 
much memory, while passing correct information to an OS image. Since using 64 
GB on i386 needs utilization of segment registers, it's overkill for GRUB.

Okuji

Re: [PATCH] new ELF64 patch

[Yoshinori K. Okuji]

On Monday 18 July 2005 00:32, Ruslan Nikolaev wrote:
> I sent new patch for mutiboot:
> http://lists.gnu.org/archive/html/grub-devel/2005-07/msg00130.html
>
>  Is it correct now?

Please give me more time. I will look at your patch, but I have things to do 
myself.

BTW, you should write ChangeLog. If you do this, it would be faster to 
proofread your patch.

Okuji

[PATCH] new ELF64 patch

[Ruslan Nikolaev]

Hi! 
 
Ok patch for x86_64 ELF64 support was rewritten. 
 
diff -urN old/multiboot.c new/multiboot.c 
--- old/multiboot.c	2005-07-17 02:50:11.978394408 +0400 
+++ new/multiboot.c	2005-07-17 02:49:41.069093336 +0400 
@@ -89,7 +89,14 @@ 
   struct grub_multiboot_header *header; 
   grub_ssize_t len; 
   int i; 
-  Elf32_Ehdr *ehdr; 
+  union { 
+    Elf32_Ehdr *ehdr32; 
+    Elf64_Ehdr *ehdr64; 
+  } hdr; 
+  union { 
+    Elf32_Phdr *phdr32; 
+    Elf64_Phdr *phdr64; 
+  } seg; 
  
   grub_dl_ref (my_mod); 
  
@@ -138,64 +145,136 @@ 
       goto fail; 
     } 
  
-  ehdr = (Elf32_Ehdr *) buffer; 
+  hdr.ehdr32 = (Elf32_Ehdr *) buffer; 
  
-  if (grub_dl_check_header (ehdr, sizeof(*ehdr))) 
+  if (hdr.ehdr32->e_ident[EI_CLASS] == ELFCLASS64) /* ELF64 */ 
     { 
-      grub_error (GRUB_ERR_UNKNOWN_OS, "No valid ELF header found"); 
-      goto fail; 
-    } 
- 
-  if (ehdr->e_type != ET_EXEC) 
-    { 
-      grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF file type"); 
-      goto fail; 
-    } 
- 
-  /* FIXME: Should we support program headers at strange locations?  */ 
-  if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > GRUB_MB_SEARCH) 
-    { 
-      grub_error (GRUB_ERR_UNKNOWN_OS, "Program header at a too high offset"); 
-      goto fail; 
-    } 
+      /* we can't use grub_dl_check_header() for ELF64 under i386/amd64 */ 
+      if (hdr.ehdr64->e_ident[EI_MAG0] != ELFMAG0 
+          || hdr.ehdr64->e_ident[EI_MAG1] != ELFMAG1 
+          || hdr.ehdr64->e_ident[EI_MAG2] != ELFMAG2 
+          || hdr.ehdr64->e_ident[EI_MAG3] != ELFMAG3 
+          || hdr.ehdr64->e_version != EV_CURRENT 
+          || hdr.ehdr64->e_ident[EI_DATA] != ELFDATA2LSB 
+          || hdr.ehdr64->e_machine != EM_X86_64) 
+        { 
+          grub_error(GRUB_ERR_UNKNOWN_OS, "No valid ELF header found"); 
+          goto fail; 
+        } 
+      if (hdr.ehdr64->e_type != ET_EXEC) 
+        { 
+          grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF file type"); 
+          goto fail; 
+        } 
+ 
+      /* FIXME: Should we support program headers at strange locations?  */ 
+      if (hdr.ehdr64->e_phoff + hdr.ehdr64->e_phnum * hdr.ehdr64->e_phentsize > GRUB_MB_SEARCH) 
+        { 
+          grub_error (GRUB_ERR_UNKNOWN_OS, "Program header at a too high offset"); 
+          goto fail; 
+        } 
+      /* we still in 32-bit mode */ 
+      if (hdr.ehdr64->e_entry >= 0xffffffff) 
+        { 
+          grub_error (GRUB_ERR_UNKNOWN_OS, "Invalid entry point for ELF64"); 
+          goto fail; 
+        } 
+      entry = hdr.ehdr64->e_entry; 
+ 
+      /* Load every loadable segment in memory.  */ 
+      for (i = 0; i < hdr.ehdr64->e_phnum; i++) 
+        { 
+          seg.phdr64 = (Elf64_Phdr *) (buffer + hdr.ehdr64->e_phoff + i * hdr.ehdr64->e_phentsize); 
+ 
+          if (seg.phdr64->p_type == PT_LOAD) 
+        { 
+          /* The segment should fit in the area reserved for the OS.  */ 
+          if ((seg.phdr64->p_paddr < (grub_uint64_t)grub_os_area_addr)  
+              || (seg.phdr64->p_paddr + seg.phdr64->p_memsz 
+              > (grub_uint64_t)grub_os_area_addr + (grub_uint64_t)grub_os_area_size)) 
+            { 
+              grub_error (GRUB_ERR_BAD_OS,  
+                  "Segment doesn't fit in memory reserved for the OS"); 
+              goto fail; 
+            } 
+ 
+           if (grub_file_seek (file, seg.phdr64->p_offset) == -1) 
+            { 
+              grub_error (GRUB_ERR_BAD_OS, "Invalid offset in program header"); 
+              goto fail; 
+            } 
+ 
+           if (grub_file_read (file, (void *)((grub_uint32_t)seg.phdr64->p_paddr), seg.phdr64->p_filesz)  
+              != (grub_ssize_t) seg.phdr64->p_filesz) 
+            { 
+              grub_error (GRUB_ERR_BAD_OS, "Couldn't read segment from file"); 
+              goto fail; 
+            } 
+ 
+          if (seg.phdr64->p_filesz < seg.phdr64->p_memsz) 
+           grub_memset ((char *)((grub_uint32_t)seg.phdr64->p_paddr) + seg.phdr64->p_filesz, 0,  
+                 seg.phdr64->p_memsz - seg.phdr64->p_filesz); 
+        } 
+        }       
+    } 
+  else /* ELF32 */ 
+    { 
+      if (grub_dl_check_header (hdr.ehdr32, sizeof(Elf32_Ehdr))) 
+        { 
+          grub_error (GRUB_ERR_UNKNOWN_OS, "No valid ELF header found"); 
+          goto fail; 
+        } 
+ 
+      if (hdr.ehdr32->e_type != ET_EXEC) 
+        { 
+          grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF file type"); 
+          goto fail; 
+        } 
+ 
+      /* FIXME: Should we support program headers at strange locations?  */ 
+      if (hdr.ehdr32->e_phoff + hdr.ehdr32->e_phnum * hdr.ehdr32->e_phentsize > GRUB_MB_SEARCH) 
+        { 
+          grub_error (GRUB_ERR_UNKNOWN_OS, "Program header at a too high offset"); 
+          goto fail; 
+        } 
+ 
+      entry = hdr.ehdr32->e_entry; 
+ 
+      /* Load every loadable segment in memory.  */ 
+      for (i = 0; i < hdr.ehdr32->e_phnum; i++) 
+        { 
+          seg.phdr32 = (Elf32_Phdr *) (buffer + hdr.ehdr32->e_phoff + i * hdr.ehdr32->e_phentsize); 
  
-  entry = ehdr->e_entry; 
- 
-  /* Load every loadable segment in memory.  */ 
-  for (i = 0; i < ehdr->e_phnum; i++) 
-    { 
-      Elf32_Phdr *phdr; 
-      phdr = (Elf32_Phdr *) (buffer + ehdr->e_phoff + i * ehdr->e_phentsize); 
- 
-      if (phdr->p_type == PT_LOAD) 
-	{ 
-	  /* The segment should fit in the area reserved for the OS.  */ 
-	  if ((phdr->p_paddr < grub_os_area_addr)  
-	      || (phdr->p_paddr + phdr->p_memsz 
-		  > grub_os_area_addr + grub_os_area_size)) 
+          if (seg.phdr32->p_type == PT_LOAD) 
 	    { 
-	      grub_error (GRUB_ERR_BAD_OS,  
-			  "Segment doesn't fit in memory reserved for the OS"); 
-	      goto fail; 
-	    } 
+	      /* The segment should fit in the area reserved for the OS.  */ 
+	      if ((seg.phdr32->p_paddr < grub_os_area_addr)  
+	          || (seg.phdr32->p_paddr + seg.phdr32->p_memsz 
+		      > grub_os_area_addr + grub_os_area_size)) 
+	        { 
+	          grub_error (GRUB_ERR_BAD_OS,  
+			      "Segment doesn't fit in memory reserved for the OS"); 
+	          goto fail; 
+	        } 
 	   
-	  if (grub_file_seek (file, phdr->p_offset) == -1) 
-	    { 
-	      grub_error (GRUB_ERR_BAD_OS, "Invalid offset in program header"); 
-	      goto fail; 
+	       if (grub_file_seek (file, seg.phdr32->p_offset) == -1) 
+	        { 
+	          grub_error (GRUB_ERR_BAD_OS, "Invalid offset in program header"); 
+	          goto fail; 
+	        } 
+ 
+	       if (grub_file_read (file, (void *) seg.phdr32->p_paddr, seg.phdr32->p_filesz)  
+	          != (grub_ssize_t) seg.phdr32->p_filesz) 
+	        { 
+	          grub_error (GRUB_ERR_BAD_OS, "Couldn't read segment from file"); 
+	          goto fail; 
+	        } 
+ 
+	      if (seg.phdr32->p_filesz < seg.phdr32->p_memsz) 
+	       grub_memset ((char *) seg.phdr32->p_paddr + seg.phdr32->p_filesz, 0,  
+			     seg.phdr32->p_memsz - seg.phdr32->p_filesz); 
 	    } 
- 
-	  if (grub_file_read (file, (void *) phdr->p_paddr, phdr->p_filesz)  
-	      != (grub_ssize_t) phdr->p_filesz) 
-	    { 
-	      grub_error (GRUB_ERR_BAD_OS, "Couldn't read segment from file"); 
-	      goto fail; 
-	    } 
- 
-	  if (phdr->p_filesz < phdr->p_memsz) 
-	    grub_memset ((char *) phdr->p_paddr + phdr->p_filesz, 0,  
-			 phdr->p_memsz - phdr->p_filesz); 
-	} 
+        } 
     } 
  
   mbi = grub_malloc (sizeof (struct grub_multiboot_info)); 
 

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Re: [PATCH] new ELF64 patch

[Hollis Blanchard]

On Jul 16, 2005, at 6:54 PM, Ruslan Nikolaev wrote:
>
> Ok patch for x86_64 ELF64 support was rewritten.
>
> diff -urN old/multiboot.c new/multiboot.c
> --- old/multiboot.c	2005-07-17 02:50:11.978394408 +0400
> +++ new/multiboot.c	2005-07-17 02:49:41.069093336 +0400
> @@ -89,7 +89,14 @@
>    struct grub_multiboot_header *header;
>    grub_ssize_t len;
>    int i;
> -  Elf32_Ehdr *ehdr;
> +  union {
> +    Elf32_Ehdr *ehdr32;
> +    Elf64_Ehdr *ehdr64;
> +  } hdr;
> +  union {
> +    Elf32_Phdr *phdr32;
> +    Elf64_Phdr *phdr64;
> +  } seg;

I don't like this. I would prefer having grub_rescue_cmd_multiboot() 
call two functions: grub_load_elf32() and grub_load_elf64():

grub_load_elf32(Elf32_Ehdr *header)
{
	if (header->e_ident[EI_CLASS] != ELFCLASS32)
		return error;

	/* load segments */
	...
}

-Hollis

Re: [PATCH] new ELF64 patch

[Yoshinori K. Okuji]

On Monday 18 July 2005 17:18, Hollis Blanchard wrote:
> I don't like this. I would prefer having grub_rescue_cmd_multiboot()
> call two functions: grub_load_elf32() and grub_load_elf64():
>
> grub_load_elf32(Elf32_Ehdr *header)
> {
> 	if (header->e_ident[EI_CLASS] != ELFCLASS32)
> 		return error;
>
> 	/* load segments */
> 	...
> }

I agree. This is more readable.

Okuji